Pettine served in the same position for the Packers last season, leading a defense that ranked No. 7 in the NFL in sacks per pass attempt (8.35 percent), with 16 different players recording at least a half-sack. It was the second most in team history (since 1982), trailing only the 1987 campaign (strike season) that featured 17 different players for Green Bay posting at least a half-sack. He helped lead the Packers to a No. 12 ranking in pass defense (234.5 yards per game) after the defense ranked No. 23 in the category in 2017. Green Bay was tied for No. 8 in the NFL with 44 sacks in 2018, the most by the Packers since 2013 (44). Last season, he also guided the Green Bay defense to a No. 9 ranking in three-and-out percentage (21.9) after the Packers ranked No. 26 in the category in 2017.

Pettine came to Green Bay after working as a consultant for the Seattle Seahawks in 2017. He previously worked as a defensive coordinator for the New York Jets (2009-12) and Buffalo Bills (2013) as well as two years as head coach for the Cleveland Browns (2014-15).

In his first season in Cleveland, Pettine guided the Browns to their most victories since 2007 as they led the league in opponent passer rating (74.1) and ranked No. 2 in interceptions (21). As a defensive coordinator with the Jets and Bills, he led his units to a top-10 finish in total yards allowed and passing yards allowed each season. In 2013, he helped the Bills rank No. 2 in the NFL with a franchise-record 57 sacks as Buffalo was the lone team in the league to have three players each register 10-plus sacks. During his four seasons with the Jets, the defense ranked No. 1 in the NFL over that span in opponent passer rating (71.0), completion percentage (52.6) and passing yards allowed per game (186.3).

Prio to being a defensive coordinator, Pettine spent seven seasons with the Baltimore Ravens, serving as a coaching and video assistant (2002), coaching assistant/quality control coach (2003), defensive assistant (2004) and outside linebackers coach (2005-08). He began his coaching career as an assistant (1988-92) for his father, Mike Sr., who was the head coach at Central Bucks West High School in his hometown of Doylestown, Pa. Pettine had a two-year stint in the college ranks as a defensive graduate assistant at the University of Pittsburgh (1993-94) before serving as the head coach at William Tennent High School (Warminster, Pa.) from 1995-96 and then at North Penn High School (Lansdale, Pa.) from 1997-2001.